This invention relates to a color picture tube and specifically relates to a flatter-face color picture tube.
In general picture tubes, shadow masks are made of low-carbon mild steel and are heated by impacts of electron beams so that they tend to deform toward phosphor screens. Such a deformation is referred to as doming. Especially, local doming generally has a considerable degree for the following reason. In a television receiver, a beam current has a limited average so that when a displayed picture has a portion brighter than other portions, the density of beam current corresponding to the bright portion is higher than that corresponding to the other portions.